Improvement in cut-off valves for steam-engines



-Engi'nes.

C. B. SHELLER;

Patented Aug. 13, I372.-

Fig.1.

M e m Improvement in- Cut-Of f Valves for Steam Witnesses.

UNITED STATES PATENT OFFICE.

CHRISTIAN B. SHELLER, on BELLEFONTAINE, oHIo.

IMPROVEMENT IN CUT-OFF'VALVES FOR STEAM-ENGINES.

Specification forming part of Letters Patent No. 130,541, dated August 1 3, 1872.

Specification describing an Improved Gut- Ofi Valve for Steam-Engines, invented by CHRISTIAN B. SHELLER, of Bellefontaine, in the county of Logan and State of Ohio.

Nature and Objects of the Invention.

.same as live steam is admitted at the oppo site end. There is but one valve-rod, the cut- 011' being carried by the main valveand actuated by the contact of a tappet-stud. This tappet is adjustable, in order that the action of the cut-0E at the respective ends of the strokemaybe equalized or varied, as required.

Description of the Accompanying Drawing.

Figure l is a plan view of a steam-chest and appurtenances, with cap removed and partly in section, illustrating the invention. Fig. 2 is a vertical longitudinal section on the line z z, Fig. 1. Fig. 3 is avertical longitudinal section, partly in elevation, and illustrating the position of the parts at a different point of the stroke. Fig. 4 is a vertical transverse section on the line y,-Fig. 2.

General Description.

The construction of the steam-cylinder A and steam-chest B forms no part of this invention. The valve-seat a. may have the common arrangement of three parts, .c s s, illustrated. The main valve 0 is a three-port slide with ports a an ac corresponding with those in the valve-seat a at bottom, and converging to a transverse cylindrical or segmental recess, b, in the top, which receives an oscillating cut-off, D, with cavity at to connect, and surfaces d d to close the said valve-ports, as required. The face of 'the main valve 0 is likewise provided, in addition to its ports, with cad surfaces 0 c" to cover the cylinder-ports E s during certain portions of the strokes. The'single valve-rod E is attached to the main valve G by yoke e, which serves also to suppor the cut ofi D from longitudinal displacement. The cut-ofl is secured against vertical displacement by bars 0', which may be adjustable. As means for actuating the cut-off a longitudinal bar, F, supporting a tappet-stud, G, is arranged in the top of the chest B, and a bracket, E, or its equivalent, presenting two arms, h h", to engage with the tappet G, is attached to the cut-off or formed thereon. The tappet G is attached to the bar F by bolts 9 passing through longitudinal slots f. 7

Operation.

Motion is imparted to the valve-rod E by any approved means, and the main valve 0, with the cut-off D, is thereby carried back and forth across the ports in the valve-seat a, so as to alternately admit steam to the respective ends of the cylinder through the ports -s s" at the ends of the valve, and to cut off the steam, and to exhaust the same in proper manner. Fig. 2 illustrates the positions of the valves at the start of the down stroke of the piston, live steam entering behind the piston through cylinder-port .9, while the other end of the cylinder is exhausting through cylinder-port s, valve-ports no as, and cavity at of the cut-off, as illustrated by arrows. The surface 01' of the cut-ofl' now closes valve-port .n'. In this condition the main valve 0 moves across the cylinder-ports, carrying the cut-oif D, without shifting the same on its axis until the surface a of the main valve closes and passes over the ports. The cut-0E D now operates to cut 011' the exhaust through valveport 00, and thus holds the steam so as to utilize its expansive force until the piston is near the end of its stroke and live steam is about to be admitted to the other end of the cylinder through cylinder-port s, when the arm h of the bracket H comes in contact with the tappet G and shifts the cut-ofi' so as to open the exhaustw to cylinder-port s through valveports 00' x and cavity d. The reverse moveinent of the piston and valve now commences, and at the proper moment steam is held by the surfaces 0 at, closing the cylinder-port s and valve-port a2, and then released by the ac tion of the tappet G through the arm k of the bracket H, opening the ports to the exhaust through valve-ports w w and cavity d, as illustrated in Fig. 2. The action of the tapp'et G may be regulated by adjusting the same by means ,of the slots f.

Claims.

The following is claimed as new: 1. Thethree-port slide-valve O and automatic cut-off D, constructed, combined, and operat- I 3. In combination with the traversing oscillating cut-ofl' D the tappet G, adjustable substantially as described, for the purpose set forth.

4. The combination of the single valve-rod E, slide-valve G, traversing oscillating cut-ofi' D, adjustable tappet G, and bracket H, constructed and operated as herein shown and described, for the purpose specified.

CHRISTIAN B. s ELnER. Witnesses:

R. H. ST. JOHN, P. JONES. 

